A research group from Holstebro Hospital in Denmark administered either 3,000 IU/day or placebo to a group of 112 hypertension patients for 20 weeks starting in either October or November. Baseline levels of 25(OH)D were 22.8 ng/ml. After 20 weeks on 3,000 IU/day, the average 25(OH)D level raised to 47.6 ng/ml in the vitamin D group.

The researchers measured before and after:

24-hour ambulatory blood pressure: this is a minute-by-minute measurement of blood pressure, so you can get a better profile of blood pressure and rule out variability depending on time of day.

pulse wave velocity: this is a measurement of arterial stiffness. Arterial stiffness is directly related to heart attack and stroke events and gets poorer as you age.

central blood pressure: this is the measurement of the pressure of the aorta, which is the large artery that the heart pumps into. It is more strongly correlated to vascular health than blood pressure measured on the upper arm. Also note that there are two reads of blood pressure: systolic, which is maximum pressure, and diastolic, which is minimum pressure.

There was no significant change in 24-hour ambulatory blood pressure. However, in patients that started below 30 ng/ml and were in the vitamin D group, they saw borderline reduction in systolic (3.7 mmHg, p = 0.08) and slightly significant diastolic blood pressure improvement (2.7 mmHg, p = 0.02) after supplementing compared to placebo.

There was no change in pulse wave velocity.

People with hypertension may now choose to use vitamin D to help in their care of high blood pressure by supplementing and maintaining better vitamin D blood levels. In this study, they found positive results in lowering blood pressure in supplementing with 3,000 IU/day and reaching vitamin D blood levels of about 50 ng/ml during the winter. Either supplementing with this dose or targeting blood levels around 50 ng/ml is suitable practice.

Make note that the Vitamin D Council recommends 5,000 IU/day because this allows a greater percentage of the population to reach vitamin D levels of 50 ng/ml. This study also highlights the importance of taking extra care in maintaining vitamin D sufficiency in the wintertime in high latitudes, when sun exposure is less frequent and not intense enough to stimulate vitamin D sufficiency.

We also recommend working with your doctor and not stopping your high blood pressure medications. If you’re interested in the use of vitamin D, print this blog out, show them this study and let them know you are interested in using vitamin D and sun exposure as part of your care of high blood pressure.

1 Response to Study: Vitamin D lowers blood pressure during winter

Vitamin D has been shown to substantially reduce hypertension. Here is a summary and a link to over 50 studies of hypertension and vitamin Dhttp://www.vitamindwiki.com/tiki-index.php?page_id=1171 Note: the lowering of blood pressure is a frequently reported side-effect by many people taking enough vitamin D for other reasons.